Colloidal semiconductor nanocrystals or quantum dots have generated significant interest for their promise in developing advanced optical materials. Size-dependent emission is attractive property of semiconductor nanocrystals allowing their use in a variety of wavelength dependent applications.
Biological labeling, for example, is expected to be a significant application of semiconductor nanocrystals. Particularly, photoluminescent (PL) quantum dots having emission in the near-infrared (NIR) region of the electromagnetic spectrum (700-1400 nm) are desirable as biological labels for in-vivo imaging because of their large absorption cross section and narrow emission bands. Moreover, semiconductor nanocrystals can also find significant application in display technologies, thermoelectrics, telecommunications and signaling, photonics and photovoltaic apparatus.
Nevertheless, the synthetic chemistry of semiconductor nanocrystals, including doped nanocrystals, is challenging and has inspired continuous efforts for developing high performance nanocrystals for use in various applications. Generally speaking, current limitations of these materials include low emission efficiency, low dopant emission characteristics, dopant ejection from nanocrystalline lattices, broad spectrum width, poor color control and/or poor stability.